Research And Exploitation On Pass-free Rolling Technology

Pass-free Rolling is an advanced technology which can optimize steel bar production. The paper investigates the development trend of pass-free rolling technology and its application results at abroad, and analyzes the feasibility of self-exploitation on pass-free rolling technology in China. The industrial experiment and the research of pass-free rolling technology are conducted on the continuous bar mill of Xinjiang Bayi Iron & Steel Co.Ltd.In the research and development, the spread characteristics of pass-free rolling are analyzed in details and the relationship among free spread, over turn spread and drum spread is pointed out. At the same time, through comparing the rolling force brought to the rolling stock by pass-free rolling and pass rolling status, it is concluded that pass-free rolling has the characteristics such as simple rolling force, uniform deformation, but difficult control, etc. On the basis of spread and rolling force on rolling stock, a spread model suitable for continuous bar mill train with long interval between stands is set up by Regression analysis.In the research of rolling stability, using predecessor's experience for reference to set up rolling model, it is concluded that the formula of max. incline angle to maintain rolling stability on continuous bar mill. Meantime, the special guide fittings suitable for pass-free rolling are designed in order to meet rolling stability.In conclusion, through quality inspection and metallographic analysis, it is proved that the pass-free rolling technology can meet higher product quality requirement and is good for production of quality steel. Practice shows that the pass-free rolling can optimize rolling sequence and can help achieve the purposes like unifying billets, descaling, saving production time, lowering roll and guide consumption, reducing workstrength and reducing fixed assets investment, etc. The pass-free rolling is a new technology, which can be applied for rank, reversible and continuous rolling mills, esp. suitable for exploitation on continuous bar mills. With greater technical and economic values, this technology has broad development and application perspective, esp. in the remoulding of old system and construction of new system in small shape production.